To keep this blunt cause I'm sleepy and cant be arsed to type or think. I've found the reason for why you can arrive at the FeeCo Depot hub and find that a door is closed as if it has already been completed. The game stores the states of the Feeco hub doors for barracks, bonewerkz and exec. office in three variables. By default the variables are each 0 which corresponds to open doors, allowing you to enter the areas. Completing barracks/bonewerkz/exec.office makes the game set the corresponding variable to 1, which the game uses to set the doors to closed to prevent entering them for a second time. Exiting to main menu doesn't reset the values back to 0, so if you exit to main menu after having completed any or all of the areas, the variables will retain their values. If you then begin a new game, and progress all the way to feeco, the variables still retain their same values and the doors at feeco will be open/closed in accordance with these values. At no point during gameplay are the values reset to 0. The only ways to reset the values back to their default starting values of 0 are by restarting the game by closing and reopening the application or by loading a savestate in which the values are each 0. Using the level skip cheat works by loading predefined save states, so doing this will load a savestate that has the appropriate variable values for the part of the game you're at, although using level skip means you're basically loading a different game other than your own, so your mudokon rescues and casualty data will not be carried over.